INward WATS is popularly known as INWATS and is frequently referred to as the "800" number toll-free telephone service. It allows a customer to establish an area of the country from which he can receive calls without charge to the calling parties. In the United States, the service is currently available for both intrastate and interstate calls. Tariff costs for the service are based on the number of customer lines, the band of rate states selected, the total monthly hours of usage, and the total number of calls completed.
Over the last decade, the volume of INWATS calls has increased to the extent that INWATS traffic has become a substantial percentage of all toll calls served by existing telephone switching systems. The service has proven to be especially useful for business customers in obtaining travel and hotel reservations, purchase orders, and the like.
Despite the commercial success of INWATS, the ever expanding customer demands for the service and the projected extension of INWATS for international calling has presented a number of problems for the telephone industry and its customers. Prevalent among the problems are: (1) the rigid geographic bands for INWATS, (2) the requirement for a multiplicity of INWATS numbers, (3) routing and numbering inefficiencies due to service entitlement check operations of originating and terminating screening offices, (4) ineffective attempts due to all INWATS customer lines busy conditions caused, for example, by mass calling to 800 numbers advertised, for example, on television, and (5) the absence of traffic statistics for INWATS customers on the number of calls made from each area code.
To elaborate, in the United States, a customer purchases the service on intrastate and/or interstate bases and is supplied with one or more INWATS numbers. Such an arrangement is necessary because of state and federal tariffs. Interstate INWATS is currently offered for a maximum of seven geographic bands. Band 1 generally involves all states bordering the customer home state; Band 2 typically includes all of Band 1 and additional states bordering Band 1; Band 5 presently covers the continental United States; Band 6 adds Hawaii and Alaska; and Band 7 includes Puerto Rico and the Virgin Islands. In some cases, multiple bands of intrastate service are also offered. Customers purchase the various service bands on a 240 hours/month or a 10 hours/month basis.
The rigid band assignment heretofore has required a customer to purchase an entire band encompassing many different telephone area codes even though the customer may desire INWATS service only in a portion of that band. A need has therefore existed for a procedure and equipment which fulfills customer requests for INWATS service covering only desired telephone area codes.
A principal INWATS problem has been the necessity for the purchaser in many instances to be assigned a multitude of different INWATS numbers. Illustratively, several airline reservation services with multiple regionalized answering points presently are provided with between 10 and 20 different INWATS numbers to obtain reasonably economical INWATS service throughout the United States. The different numbers are required by the customer because of geographical location, business hours and the designs and operations of existing switching equipment. Such multiple number requirements have proven to result in customer and user confusion, errors in directory number listings and advertising, as well as complications in obtaining directory assistance for nonlocally published INWATS numbers and in conformity with the call originating area codes. New call processing techniques and facilities are therefore needed to eliminate the plural numbers for each INWATS customer.
An INWATS number presently includes a special area code of 800, followed by a specific NNX code for the terminating NPA (Number Plan Area), followed by a four digit number XXXX. "N" in the code refers to any digit except 0 or 1 and "X" refers to any one of 10 digits. Of the NNX codes, all NN2 codes are currently reserved for intrastate use. At the present time, each NPA in the United States is assigned one NNX code with the exception of the NPAs 212, 312 and 213 each of which have two NNX codes.
INWATS number usage is readily understood by considering an example of a typical INWATS call. Assume that a party in Indianapolis wishes to place a call to an INWATS customer with the assigned number 800+241+2312 in the Atlanta, Georgia area. After the caller dials the number, the call is routed to an originating screening office which utilizes the 800+241 to determine both the terminating city (Atlanta) and the band of the calling party with respect to the terminating city. The screening office then sends a number 142+2312 to a terminating screening office for Atlanta. The underlined "2" indicates that Indianapolis is in Band 2 with respect to Atlanta and the "4" represents the 241 NXX code. On the basis of the received 142+2312, the terminating screening office ascertains whether or not the call originated from a permissible rate band purchased by the called custmer. If the call is entitled to be completed, the terminating screening office controls the establishment of call connections to the called customer.
A disadvantage of the foregoing INWATS call processing arrangements is that INWATS call screening, routing and service entitlement checking functions are performed by costly, complex and special INWATS facilities integrated into many individual originating and terminating screening offices throughout the nation and without call rerouting capability in such offices in the event of call overload or equipment failure. Another disadvantage is that no procedure is available for determining the busy condition of INWATS customer lines before calls are switched through the toll network. Present day switching systems determine that all INWATS customer lines are busy only after the calls are routed through the originating and terminating screening offices to the local terminating office. As a consequence, the telephone network occasionally is overloaded, particularly during heavy traffic periods by mass calling to the all busy INWATS customer lines. Such overloads obviously are undesirable and prove to be a problem for telephone companies especially because no facilities are available for dynamically identifying INWATS customer busy conditions and then precluding the toll switching of INWATS calls to that customer.
Another disadvantage is that existing telephone systems and call processing techniques have been unable to provide adequate traffic data to INWATS customers on the number of calls received from a given geographic area. The data would aid in the determination of the numbers of INWATS lines and stations as well as the personnel needed to serve the calls. It would also enable customers to determine whether the serivce is economically warranted for that area.